Gonadotropin releasing hormone agonist

Gonadotropin-releasing hormone agonist
Drug class
Leuprorelin (leuprolide), one of the most widely used GnRH agonists.
Class identifiers
Synonyms	GnRH receptor agonists; GnRH blockers; GnRH inhibitors; Antigonadotropins
Use	Infertility; Prostate cancer; Precocious puberty; Breast cancer; Endometriosis; Uterine fibroids; Transgender people
Biological target	GnRH receptor
Chemical class	Peptides

A gonadotropin-releasing hormone agonist (GnRH agonist, GnRH–A) is a type of drug that acts as an agonist of the GnRH receptor, the biological target of gonadotropin-releasing hormone (GnRH). These drugs can be both peptides and small-molecules. They are modeled after the hypothalamic neurohormone GnRH, which interacts with the GnRH receptor to elicit its biologic response, the release of the pituitary hormones follicle-stimulating hormone (FSH) and luteinizing hormone (LH). However, after the initial "flare" response, continued stimulation with GnRH agonists desensitizes the pituitary gland (by causing GnRH receptor downregulation) to GnRH. Pituitary desensitization reduces the secretion of LH and FSH and thus induces a state of hypogonadotropic hypogonadal anovulation, sometimes referred to as “pseudomenopause” or “medical oophorectomy.”

GnRH agonists are pregnancy category X drugs.

GnRH agonists are useful in:

Women of reproductive age who undergo cytotoxic chemotherapy have been pretreated with GnRH agonists to reduce the risk of oocyte loss during such therapy and preserve ovarian function. Further studies are necessary to prove that this approach is useful.

Side effects of the GnRH agonists are signs and symptoms of hypoestrogenism, including hot flashes, headaches, and osteoporosis. In patients under long-term therapy, small amounts of estrogens could be given back (“add-back regimen”) to combat such side effects and to prevent bone wastage. Generally, long-term patients, both male and female, tend to undergo annual DEXA scans to appraise bone density.